The professor who is giving concrete a new lease of life

In Kolkwitz, a two-storey extension is currently being built onto the clubhouse, which was erected in 2009, using recycled concrete elements – around 60 concrete slabs from a partly demolished and converted block of flats in nearby Großräschen, some of which are up to six metres long and weigh just under six tonnes. In addition, a ticket office and a garage for two minibuses are being built in the entrance area using 21 reused concrete elements. 

Her work is made possible by her fundamental research and scientific contributions to the international, EU-funded Horizon 2020 project “ReCreate”. As part of this project, the researcher is working with European partners to develop procedures, standards and digital tools so that reused precast concrete elements can be systematically incorporated into new construction projects in future. Kolkwitz is, in a sense, providing the practical proof for this. The construction of the shell is being scientifically monitored by the BTU. Thanks to funding for the finishing works as part of the “ReUse Hub” project – planned and supervised by the Cottbus-based engineering firm Jähne – these buildings will be completed before the end of this year.   

A pioneer of an idea

Mettke heads the Structural Recycling field of study at the BTU. Her basic idea is put simply, but has far-reaching implications: not to dispose of building components from old buildings, but to reuse them in new projects. What is now discussed under the terms ‘circular economy’ and ‘circular construction’ has been a driving force for the Cottbus native for around three decades – long before the topic gained political momentum.

Gravel, sand, limestone and clay do not grow back

For Mettke, the concrete elements from GDR prefabricated blocks of flats are not a burden on the environment, but – as she herself puts it – a treasure trove. The real waste, she argues, lies not in continuing to build with used parts, but in thoughtless demolition. She sums up her argument as follows: “Gravel, sand, limestone and clay do not grow back.”

According to her own calculations, reusing existing building components can reduce CO₂ emissions by up to 97 per cent compared to those generated by new production – a figure that is sure to catch people’s attention in the context of the climate debate. In October 2025, Mettke was honoured for her life’s work at the Betongdagen in Stockholm with the Swedish Concrete Award, the highest distinction from the Swedish Concrete Association.

Research with a direct link to the building site

Mettke’s work does not remain confined to theory. Her findings arise from constant dialogue with engineering firms, demolition contractors, local authorities and developers from both the region and further afield, and are – as in Kolkwitz – tested directly on real construction sites.

In doing so, she also clearly identifies structural problems: developers wishing to use second-hand building components often ended up contacting her department directly, for want of any other point of contact. “That can’t be right,” says Mettke. Her team is therefore working in parallel to set up marketing platforms for reusable building components, so that sustainable construction does not remain the exception but becomes the norm.

The project in Kolkwitz is a prime example of how regional research provides practical answers to big questions: how to conserve resources, reduce emissions and, at the same time, keep sustainable construction affordable. For Angelika Mettke, the solution does not lie in new materials – but in taking a fresh look at what has long been available.